1. Field of the Invention
The present invention generally relates to a computer enclosure, and in particular to a computer enclosure having a double-layered structure for providing excellent electromagnetic interference (EMI) protection and mechanical properties.
2. The Prior Art
A personal computer comprises an enclosure for accommodating computer components therein. The computer enclosure comprises bottom, top, front, rear and side panels made from metal plates. Gaps may exist between adjacent panels through which leakage of electromagnetic radiation occurs, and long term exposure to electromagnetic radiation is known to be harmful. To overcome the problem of leakage of electromagnetic radiation, resilient metal members are interposed between adjacent panels for blocking the gaps. The resilient metal members increase costs and complicate manufacture of computer enclosures but may not be completely effective in reducing leakage of electromagnetic radiation. In addition, the front panel of a computer enclosure is usually formed with openings for mounting disk drives and ventilation holes for heat removal. Such openings and holes magnify the severity of the electromagnetic radiation problem. Techniques that are taken to address the radiation problem of a computer enclosure are disclosed in Taiwan Patent Application Nos. 74223527, 75227324, 71223379, 74211627 and 74223527 and U.S. Pat. Nos. 5,164,776, 5,031,070 and 5,491,610.
It is thus desired to provide a double-layered computer enclosure which effectively prevents leakage of electromagnetic radiation through a front panel thereof.
Accordingly, an object of the present invention is to provide a double-layered computer enclosure having excellent EMI protection and mechanical properties.
Another object of the present invention is to provide a computer enclosure having a double-layered front panel for reducing leakage of electromagnetic radiation through the front panel.
To achieve the above objects, in accordance with the present invention, a computer enclosure comprises an outer casing having at least a bottom plate and a first front plate. A number of first tabs is formed on the first front plate. Each first tab is associated with an opening defined in the first front plate. An inner casing is received in the outer casing and is movably supported on the bottom panel. The inner casing has at least a second front plate abutting against the first front plate of the outer casing. Second tabs are formed on the second front plate for being received in the openings of the outer casing and abutting against the corresponding first tabs for positioning the inner casing with respect to the outer casing and establishing a grounding path therebetween. The openings of the outer casing are shielded by the second front plate of the inner casing thereby preventing leakage of electromagnetic radiation therethrough.